The present invention relates generally to the field of resource allocation in computing systems, and more particularly to managing power in such systems.
In system virtualization, multiple virtual computing systems are created within a single physical computing system. The physical system can be a stand-alone computer, or alternatively, a computing system utilizing clustered computers and components. Virtual systems are independent operating environments that use virtual resources made up of logical divisions of physical resources such as processors, memory, and input/output (I/O) adapters. System virtualization is implemented through some managing functionality, typically hypervisor technology. Hypervisors, also called virtual machine managers (VMMs), use software or firmware to achieve fine-grained, dynamic resource sharing. Hypervisors are the primary technology for system virtualization because they provide the greatest level of flexibility in how virtual resources are defined and managed.
Hypervisors provide the ability to divide physical computing system resources into isolated logical partitions. Each logical partition operates like an independent computing system running its own operating system (e.g., a virtual system). Operating systems running in a virtualized environment are often referred to as “guest machines.” Exemplary operating systems include AIX®, IBM® i, Linux®, and the virtual I/O server (VIOS). Hypervisors can allocate dedicated processors, I/O adapters, and memory to each logical partition and can also allocate shared processors to each logical partition. Unbeknownst to the logical partitions, the hypervisor creates a shared processor pool from which the hypervisor allocates virtual processors to the logical partitions as needed. In other words, the hypervisor creates virtual processors from physical processors so that logical partitions can share the physical processors while running independent operating environments.
The hypervisor can also dynamically allocate and de-allocate dedicated or shared resources (such as processors, I/O, and memory) across logical partitions while the partitions are actively in use. This is known as dynamic logical partitioning (dynamic LPAR) and enables the hypervisor to dynamically redefine all available system resources to reach optimum capacity for each partition.
One aspect of dynamic resource allocation that is often ignored is power consumption. Although power consumption tends to correlate with the amount and type of allocated resources spikes in power consumption may come at unexpected times. Such spikes require computing systems to have larger power supplies and may increase utility bills which are often based on peak usage. The ability to better control power consumption spikes would be an advancement in the art.